Hydraulic apparatus



2 Sheets-Shaet l F. J. WRIG HT HYDRAULIC APPARATUS Filed June 19, 1943ATTORNEY ug. 23, 1949. F. J. WRIGHT HYDRAULIC APPARATUS 2 Sheets-Sheet 2Filed June 19, 1943 INV ENTOR FRED lmmm BY ffy/61M may,

ATTORNE Patented Aug. 23, 'i949 HYDRAULIC APPARATUS Fred J. wright,columbus, om, assigner u The Denison Engineering Company,

Columbus,

Ohio, a corporation of Ohio Application June 19, 1943, Serial No.491,498

6 Claims. (Cl. 10S-162) I'he present invention relates to iiuid pressureenergy translating devices such as hydraulic motors and pumps and moreparticularly to motors and pumps employing a cylinder barrel,reciproeating pistons therein and an associated angularly disposedthrust plate or ring which, when relative rotation is imparted betweenthe elements of the motor or pump, causes reciprocation of the pistons.

One of the objects of the present invention is to provide a translatingdevice of the above mentioned type in which the driving connection,between the barrel and shaft. is disposed so that the resultant forcesof thrusts, created by the association of the pistons with the thrustring, pass from the barrel to the shaft at the connection.

In translating devices of the type above mentioned, a shaft is employedfor driving the barrel when the device functions as a pump or the shaftis driven by the barrel when the device functions as a motor. A drivingconnection, such as a spline, is interposed between the barrel andshaft.

Another object of the present invention is to provide a hydraulic pump,or motor, comprising a barrel having one or more cylinders formedtherein, and pistons in the cylinders, the pistons being forcedoutwardly against piston actuating mechanism by a spring, which springreacts against the barrel for urging the barrel into frictionalengagement with a member having ports for supplying liquid to anddirecting the liquid from the cylinders.

Another object of the invention is to provide a coil spring for reactingbetween the cylinder barrel of a pump, or motor, and the piston in acylinder of the cylinder barrel, which spring is mounted at one end on afriction reducing bearing.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred form of embodiment of the invention isclearly shown.

In the drawings:

Fig. 1 is a view, partly in section, of a hydraulic pump embodying theinvention;

Fig. 2 is a perspective view of a spring support member;

Fig. 3 is an end view of the cylinder barrel as viewed on the line 3-3of Fig. 1;

Fig. 4 is an end view of the port plate as viewed on line 4-4 of Fig. 1;

Fig. 5 is a view similar to Fig. 1 but illustrates more clearly one ofthe features of the invention; and

`2 Fig. 6 is a diagrammatic view showing the relation of the cylinderbarrel and pistons to the thrust ring and the forces acting on theseelements during the operation of the device.

Although the present invention is directed broadly to iiuid pressureenergy translating de vices, such as fluid motors or fluid pumps, I haveshown the same as a hydraulic pump merely for the purpose ofillustrating one embodiment of the invention.

Referring tothe drawings, I have shown a hydraulic pump 2li comprising ahousing 2l formed by cylindrical housing sections 22 and 23 joinedtogether, by bolts 24. One end of the section 23 is closed by a cap orport plate 26, which plate is attached to the housing by bolts 21. Adrive shaft 30 is journaled at one end in a bearing 3| in the plate 26and adjacent the other end by a bearing 32, which bearing is in thehousing section 22. The shaft 30 is splined at 34 and a barrel 35 iskeyed to the shaft 3i! by the splines 34. The barrel 35 is disposed inhousing member 23 and is provided with a plurality of cylinders, one ofwhich is shown in Fig. 1 at 36, which cylinders' extend parallel withthe axis of the barrel and are spaced equally from one another about thebarrel and at equal distance from the axis of the barrel. Each of thecylinders 36 has a port 31 leading from the end face 38 of the barrel 35to the cylinder through which liquid is taken into and discharged fromthe cylinder. The face 38 of the barrel is maintained in frictionalengagement with the face 39 of the port plate 26 as will be more fullyexplained hereinafter.

A cylindrically shaped piston 40 is provided for each cylinder, whichpiston is closed at 4I, the opposite end being open. The outer end 4 l'of the pistons 40 are shaped spheroidally, the purpose of which willappear hereinafter. Coil springs, one of which is shown at 44, aredisposed within the pistons 40, an end of each spring abuts the closedend 4I cf a piston and the opposite end being supported by freelyrotatable bearings 45. The bearings 45, only one being shown, eachcomprise an open end spring retainer support 46 disposed in a cylinder3B and having three openings 41 in the sides and a spindle 48extending'from the closed end thereof. The open end of the support 46abuts the end of the cylinder'36 and surrounds the port 31. The openings41 form passages through which the liquid passes to and from thecylinders. A spring retainer in the form of a thimble 49 is rotatablysupported on the spindle, and the spring 44 abuts a peripheral ange 50of the thimble 49. Theend of the spindle 48 is spheroidically shaped andthe side walls and end are highly polished; likewise the inside of thethimble 49 is highly polished so that the thimble 49 rotates freely onthe spindle. Since the liquid handled by the pump is oil, the bearing iswell lubricated.

A cylindrical thrust plate 52 is rotatably supported by and within thehousing section 22 by a -ball bearing 53. The plate 52 is supported sothat the axis thereof is tilted with respect to the axis of the cylinderbarrel 35. The pistons 40 are biased outwardly and into engagement withthe face 54 of the plate 52. It is apparent that when the drive shaft 30is rotated, the cylinder barrel 35 will be rotated and the springs 44,together with the camming effect of the plate 52, will cause the pistons40 to be reciprocated in the cylinders 36.

The end cap or port plate 26 is provided with arcuate oil inlet andoutlet ports 55 and 56 in the face 39 thereof, and the ports 31 of thecylinders 36 progressively register, rst with one of these ports andthen the other as the barrel 35 rotates so that oil is drawn into thecylinders 36 as the pistons 40 move outwardly, and, as the pistons aremoved inwardly, the oil in the cylinders 36 is forced. out through theother arcuate port. The ports are connected with conduits, not shown,for directing the oil Ato and from the pump.

' 44 with the cylinder barrel 35 and the opposite ends of the springswith the pistons 30, the springs 'provide a reacting force between theplate 52 and the barrel for urging the barrel against the face 39. Afterthe pistons 40 have commenced to pump oil, the pressure of the oilagainst the port end of the cylinders urges the barrel 35 into contactwith the face 39 of the port plate.

By forming the ends 3| of the pistons 40 spheroidally, a minimum of areaof the piston will engage the plate 52 thereby minimizing friction. Itis apparent that the ends of the pistons will engage the face 54 of theplate 52 at one side of the axis of the pistons and when the barrel 35rotates, the pistons will be rotated about their axes. Since the springs44 connect directly with the pistons 40, although merely by friction,the springs will have a tendency to rotate about their axis with thepistons. By supporting the opposite ends of the springs by a bearingwhich is freely rotatable, the springs will rotate with the pistons andare, therefore, not subject to an appreciable torsional strain. andthere is no frictional sliding between the pistons and springs. Thislengthens the effective life of the springs and prevents wearing on theinside of the pistons.

Referring particularly to Fig. 6, it will be seen that the splineconnection 34, between the shaft 30 and barrel 35, is disposed where theresultant of the components of the thrusts, created by the 'relationshipof the pistons 40 and the thrust plate 52, is transferred from thebarrel to the shaft. This is apparent since there are two components offorce acting on each piston, these being indicated by lines A and "B,"The resultant force on each piston is indicated by a line C. The lengthof line B is determined by the center of the radius for the spheroidicalend 75 4I of the piston. These centers are indicated by "D. The startingpoints or nucleuses of the resultant forces fal1 within a plane "D.Therefore, the seven resultant forces indicated by the lines C of thecomponent forces A" and B, fall axially within the connes of the splineconnection 34.

By arranging the spline as herein disclosed, the resultant forcestransmitted between the barrel and shaft are all substantiallydownwardly, as viewed in Fig. 6, with the result that the resultantforce urging the face of the barrel against the face of the port plateis substantially parallel with the axis of the barrel, that is, theresultant force, created by the association of the pistons with thethrust ring, is substantially at right angles to the engaging faces ofthe barrel and port plate. Consequently, torsional strain at these facesis reduced to a minimum. Moreover. the thrust between the thrust ringand the piston is at right angles to the ring and thereby wear on theends of the pistons, the thrust ring and the bearing for the latter isreduced to a minimum.

While the form of embodiment of the present invention as hereindisclosed constitutes a preferred form, it is to be understood thatother forms might be adopted, all. coming within the scope of the claimswhich follow:

I claim;

1. A fluid pressure energy translating' device comprising a cylinder.barrel having a plurality of piston chambers with ports adjacent oneend thereof; pistons disposed in said chambers, said pistons comprisingcylindrical members closed at one end and open at the opposite end, saidopen ends facing toward the ends of the chamber provided with saidparts; coil springs having one end thereof extending into said pistonsand connected therewith; bearing members comprising base elementsabutting said ported ends of said chambers,l said base elements beingopen for the passage of fluid therearound; and means forming rotatableconnections betwen said base elements and said springs.

2. A fluid pressure energy translating device comprising a'cylinderbarrel having a plurality of piston chambers with ports adjacent theinner ends thereof; pistons slidably mounted in said chambers, saidpistons, being hollow and having closed ends projecting from saidchambers; tapered coil springs disposed within Asaid pistons; means atthe closed ends of said pistons for locating the small end of thesprings in spaced relation from the side walls of said pistons; bearingmembers abutting the ported ends of said chambers, said bearing membersbeing open for the passage of uid therethrough, and means on saidbearing members for rotatably supporting the other ends of said springsin spaced relation from the walls of said pistons.

3. A uid pressure energy translating device comprising a cylinder barrelhaving a plurality of piston chambers with ports adjacent the inner endsthereof; pistons slidably mounted in said cylinders, said pistons beinghollow and having closed ends projecting from said chambers; taperedcoil springs disposed in said chambers; means for preventing theengagement between said springs and the side walls of said pistons, saidmeans having base elements disposed at one end of said chambers; meanson said base elements for rotatably supporting and locating one end ofsaid springs; and, means frictionally engaging the springs at theopposite ends of the chambers for holding the springs away from thepiston side walls.

4. A fluid pressure energy translating device comprising a cylinderbarrel having a plurality of piston chambers with ports-adjacent theinner -ends thereof; pistons slidably mounted in said cylinders, saidpistons being hollow and having closed ends projecting from saidchambers; tapered coil springs disposed in said chambers; means forpreventing the engagement between said springs and the side walls ofsaid pistons, said means having sockets provided at one end of thechambers to receive the small ends of said springs; and, base membersdisposed at the opposite ends of said chambers, said base members havingbearing and spring receiving and centering devices rotatably supportedon said bearings.

5. In a fluid motor, a casing; a port plate in saidcasing; a cylinderbarrel disposed with one end wall in sliding engagement with said portplate, the remaining walls being spaced from the walls of said casing,said cylinder barrel having a central opening and cylinders parallelwith and spaced from said opening; piston means disposed forreciprocation in said cylinders, said pistons having spheroidally shapedends the centers of generation of which are dis sed in the axial centersof said pistons; an inclined thrust member disposed in engagement withsaid ends of said pistons; a shaft extending into the central opening insaid cylinder barrel; and a splined driving connection between saidshaft and said cylinder barrel, said connection extending a limiteddistance on either side of a plane passing through the centers ofgeneration of the spheroidal ends of said pistons.

6. In a fluid motor, a casing; a port plate in said casing; a cylinderbarrel disposed with one end wall in sliding engagement with said portplate, the remaining walls thereof being spaced from the walls of saidcasing, said cylinder barrel having an axial opening and cylindersparallel with the longitudinal axis thereof; piston means disposed forreciprocation in said cylinders and projecting from the end of saidcylinder barrel opposite that engaging said port plate; the outer endsof said pistons being spheroidallyshaped and having the centers ofgeneration thereof in the axial centers of said pistons and near theadjacent end of said cylinder barrel; an inclined thrust member disposedin engagement with said ends of said pistons; a shaft extending into theaxial opening in said cylinder barrel; and a loose splined drivingconnection between said shaft and said cylinder barrel, said connectionbeing located adjacent the end of said cylinder barrel from which saidpistons project.

` FRED J. WRIGHT.

REFERENCES CITED The following references are of record in the ille ofthis patent:

UNrrED STATES PATENTS Numberl Name Date 1,820,266 Bilderdeck Aug. 25,1931 1,924,738 Flanders Aug. 29, 1933 1,970,133 Ferris et al Aug. 14,1934 2,071,800 Mock Feb. 23, 1937 2,093,477 Parsons Sept. 21, 19372,096,907 Linderman Oct. 26, 1937 2,107,079 Mentele Feb. l, 19382,129,828 Dunn Sept. 13, 1938 2,129,886 Syrovy Sept. 13, 1938 2,161,143Doe et al. June 6, 1939 2,248,449 Dudley July 8, 1941 2,292,125 fieldAug. 4, 1942 2,299,233 Hoffer Oct. 20, 1942 2,300,009 Rose Oct. 27, 19422,331,694 Jeffrey Oct. 12, 1943 Certificate of Correction Patent No,2,480,069 August 23, 1949 FRED J. WRIGHT It is hereby certiied thaterrors appear in the printed specification of the above numbered patentrequiring correction as follows:

Column 4, line 38, for the word parts read ports; line 50, after"pistons strike out the comma;

and that the said Letters Patent should be read with these correctionstherein that the same may conform to the record of the case in thePatent Office.

Signed and sealed this 7th day of March, A. D. 1950.

low-l THOMAS F. MURPHY,

Assistant ommz'asoner of Patemta

